HVAP 及 HVOF 工艺制备 WC10Co4Cr 复合涂层及其性能研究

目的对比研究超音速等离子喷涂(HVAP)技术与超音速火焰喷涂(HVOF)技术制备WC10Co4Cr涂层,并根据涂层组织形貌与电化学特性判断两种工艺的优劣。方法采用SEM及XRD分析WC10Co4Cr复合涂层的微观形貌和物相,在3.5%(质量分数)Na Cl溶液中对涂层进行电化学分析。结果 WC10Co4Cr涂层由较大的WC颗粒及粘结相组成,在喷涂过程中WC颗粒不断累积形成层片状结构,涂层有较小程度的失碳,形成了具有脆性的W2C。电化学极化测试表明,超音速等离子喷涂技术制备的涂层表现出优异的抗电化学腐蚀性能。结论超音速等离子喷涂技术制备的WC10Co4Cr涂层显微硬度为1197HV,孔隙率为0.50%,腐蚀电位为-0.3947 V,腐蚀电流密度为9.19×10-7A/cm2,腐蚀速率为1.01×10-2g/(m2·h),腐蚀深度为1.09×10-2mm/a,具有与超音速火焰喷涂涂层相似的耐腐蚀性能。

Properties of WC10Co4Cr Composite Coatings Prepared Using HVAP and HVOF Technologies

Objective WC10Co4Cr coatings prepared by high velocity air plasma (HVAP) and high velocity oxy-fuel spraying (HVOF) were comparatively studied, and the advantages and disadvantages of the two technologies were judged by the morphology and electrochemical property of the coatings prepared. Methods The microstructure and phase constitution of the WC10Co4Cr composite coatings were analyzed by SEM and XRD, and the electrochemical analysis of the coatings was performed in 3. 5% (mass fraction) NaCl solution. Results The morphology results showed that the coatings were composed of relatively large WC ceramic particles and metallic binders, and lamellar structures were formed during the coating process by the steady accumulation of WC particles. The coatings showed a small degree of carbon loss, and formed W2C with brittleness. The potentiodynamic polarization test revealed that the WC10Co4Cr coating prepared by HVAP showed excellent electrochemical corrosion resistance. Conclusion The WC10Co4Cr coating prepared by HVAP had a microhardness of 1197HV, a porosity of 0. 50% , a corrosion potential of -0. 3947 V, a corrosion current density of 9. 19×10 -7 A / cm2 , a corrosion rate of 1. 01×10 -2 g / (m2 ·h), and a corrosion depth of 1. 09×10 -2 mm / a, and showed a similar corrosion resistance with the coating prepared by HVOF.